In this Monday Morning Minute, we demonstrate how to limit the speed of the pump using the Danfoss Variable Frequency Drive (VFD).
Parallel Pumping: 2-Position Control Valves on Multiple Cooling Towers
Over the last few weeks the Monday Morning Minutes posts have looked at pumping issues with multiple condensers and pumps. One of our most-received questions …
Parallel Pumping in Condenser Applications: Automatic Differential Pressure Control (Part 3)
Chilled water condensers are normally operated as constant-flow devices and the pumps serving them are constant-speed. Why would you ever use a variable-speed drive for …
Parallel Pumping in Condenser Applications: Limiting the Flow Rate (Part 2)
In part 1 of this series we offered an example condenser water pumping system. The design of this example is 800 GPM per condenser for a …
Parallel Pumping in Condenser Applications (Part 1)
Applying a single constant-speed pump for each condenser in a chilled water application is a normal design for the HVAC engineer. The chiller manufacturers suggest …
Variable Speed Hydronic Pump Selection – Should I Specify the Largest Impeller?
We recently received an inquiry from an engineering firm deciding whether to change their pump schedule. They currently select the pumps at design capacity and …
Smart Variable Speed Centrifugal Pumps: Part 2 (Base Mounted)
Larger centrifugal pumps with horsepower over five are a great place to save energy in HVAC and plumbing systems. Historically, these larger pumps were typically …
Smart Variable Speed Centrifugal Pumps: Part 1 (Line Mounted)
This week and next we will talk about centrifugal pumps with the variable speed technology built into them. These pumps are called “Smart pumps.” Why …
B&G Systemwize: Overspeeding of Variable Speed Pumps
The term “overspeeding” in pump selection and operation is a topic of conversation in the world of hydronic design. When asked about this subject I …
How to Pick an HVAC Centrifugal Pump Part 9: Over Speeding HVAC Pumps & Motors
There are times when a little more capacity or a little more safety factor is needed from a pump selection. Often, we are asked about …